Decomposition of Mulches
in No-till Organic Systems

By Caroline Halde, Ph.D. student

Creating a barley-hairy vetch mulch using the roller-crimper.

Weed control is rated one of the greatest challenges faced by Canadian organic growers (OACC 2008). Canadian organic farmers rely on mechanical practices to control weeds, such as tillage, as the use of chemical herbicides is restricted in organic production. However, frequent tillage on organic farms leads to soil degradation, environmental pollution, and fossil fuel dependency (Zentner et al. 2004).

One way to reduce tillage on organic farms without using herbicides is to integrate the use of mulches in the cropping system. The mulch farming system has been widely used by Brazilian no-till farmers for over three decades (Bernoux et al. 2009). The mulch plays various roles in the cropping system, including water retention, weed suppression, and reduction of synthetic pesticide use. The mulch production systems may be an option for Canadian organic farmers interested in reducing tillage on their farms. In Western Canada, roller-crimpers have been used as an alternative to chemical herbicides to terminate a green manure crop. The rolling action crimps the plant stem, leaving a mulch on the soil surface, thereby eliminating the need for tillage to terminate the crop.

The objective of my study is to examine the feasibility of implementing no-till practices in organic grain production systems in Western Canada. Moreover, we want to assess the ability of different plant species combinations mixture to produce mulch and its impact on subsequent crop productivity.